This Sunday, the first after Pentecost, is known as "Trinity Sunday." The idea is to celebrate the Trinitarian nature of God--that know God to be composed of Father, Son, and Holy Spirit and to function as Creator, Redeemer, and Sustainer. The Doctrine of the Trinity is a famously difficult and complex teaching of the church. Like most doctrines of Christian belief, it is an attempt to make sense of an experience of God we have embed in the scripture: how can we say that Jesus is God and yet somehow not the same as the God who created heaven and earth? Also, how can we say that the Spirit of God, given at Pentecost, both is and isn't God? Understanding the relationship between Jesus, God, and the Holy Spirit was the great controversy that occupied the great minds of Christianity up until at least 325 (The First Council of Nicaea, from which we gained the great Nicene Creed).
At the heart of the "problem" of the Trinity is that God has revealed himself to us fully in the being of his Son. We believe that Jesus was not only the Son of God, but that that the full essence of God came to dwell with us in that person. How do we express what we know about this arrangement except with the language of relationship? All doctrines of the Trinity are attempts to express that at the heart of the mystery of God is a relationship.
What is striking, theologically, is that we hold that this aspect of God is not merely a result of our limited capacity to understand, a prism through which God passes in order to be known to us, but actually is true of God even in Himself. In other words, even before humankind or the world were created, God already existed as Father, Son, and Holy Spirit. The Trinity didn't start with the birth of Jesus, it was there from the beginning.
Often we tend to think of human beings as being individuals first, and then as members of social and familiar groups as providence and choice has determined. But, in fact, it would be more correct to think of families and other social groups as existing first, and individuals arising out of them. For the first months of life, an infant is incapable of recognizing that they are a separate being from her mother, but gradually this sense of separateness emerges.
There is grace in the Doctrine of the Trinity because it shows that God, like humankind created in God's image, is inherently social. We are not alone, but emerge out of a great web of relations that go far beyond anything we can imagine. We are children of God, away at University, perhaps, but fated to come home after graduation.
Father, we praise you: through your Word and Holy Spirit you created all things. You reveal your salvation in all the world by sending to us Jesus Christ, the Word made flesh. Through your Holy Spirit you give us a share in your life and love. Fill us with the vision of your glory, that we may always serve and praise you, Father, Son, and Holy Spirit, one God, for ever and ever. Amen.